perisarc


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Related to perisarc: Coenosarc

perisarc

[′per·ə‚särk]
(invertebrate zoology)
The outer integument of a hydroid.
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References in periodicals archive ?
Hydrothecae deeply campanulate, quite cone-shaped, about 727-935 [micron]m long, 387-528 [micron]m wide at margin, 159-241 [micron]m wide at diaphragm, with thin perisarc. Walls convex above diaphragm, nearly straight elsewhere; margin with about 11 to 17 deeply cut, blunt, triangular cusps separated by U-shaped incisions.
Hydrothecae of moderately thin perisarc, campanulated, urn-shaped, 587-976 pro long, 95-137 [micron]m wide at diaphragm, 229-399 pro wide at margin; convex walls above diaphragm, nearly straight elsewhere.
Pedicels very long, about 18-20 mm, thick perisarc, with 3-4 occasional groups of annuli irregularly placed along length; groups with 3-7 annuli; distal end of pedicel with slight swelling just beneath a sub-hydrothecal spherule.
Description: Stolonal or erect colonies, with brownish and thick perisarc. Stolonal forms, up to 6 mm high, arising from a creeping hydrorhiza; erect forms branching sympodially up to 13 mm high, but usually 10 mm.
During the course of our microscopic examination, one planula successfully bored through the outer, "shell-like" perisarc (within 5-50 min), emerging as swimming planula (Fig.
At closer examination the pattern of the colonies is fixed by a rigid outer skeleton, the chinitous perisarc. We are interested in how this perisarc is shaped.
Inside the perisarc is a hollow tube of soft tissue composed of two cell layers separated by an extracellular matrix, the mesogloea.
All parts of the colony are covered with the perisarc. In thecates, the polyp expands out of the tubelike endings of the perisarc covering (Fig.
The perisarc of the stolons is an almost uniform tube that is flattened at the site of tight contact to the substratum.
The surface at this stage is smooth and covered with perisarc material.
The surface of the immature polyp below the region of the head is covered with perisarc.
A mouth is present at the very tip of the hypostome just above the whorl of capitate tentacles, a perisarc covers the stalk and basal region of the polyp, and stolon formation has begun in the basal region of the polyp [ILLUSTRATION FOR FIGURE 8 OMITTED].